WO2004042130A1 - Spun bonded nonwoven fabric, laminates made by using the same, and processes for production of both - Google Patents

Abstract

A spun bonded nonwoven fabric which is constituted of conjugated fibers (1) made of a combination of at least two polymers selected from among (1) ethylene polymers specified in melt flow rate (MFR), density, and Mw/Mn ratio (wherein Mw is weight-average molecular weight and Mn is number-average molecular weight), (2) specific propylene block copolymers which each contain both a part soluble in n-decane at 25°C and a part insoluble therein at 25°C, and (3) propylene polymers other than the block copolymers (2) and which has a specific volume of 10 cm3/g or above; and laminates which each comprise as the essential constituents both a layer of the above spun bonded nonwoven fabric and a layer of a nonwoven fabric having a specific volume smaller than that of the spun bonded nonwoven fabric.

Description

 Description Spunbond nonwoven fabric and laminate using the same,

 And their manufacturing methods

 The present invention relates to a spunbonded nonwoven fabric, a laminate using the same, and a method for producing the same. More specifically, the present invention relates to a spunbonded nonwoven fabric which is appropriately shrunk and has excellent flexibility, a laminate using the same, and a method for producing these. Background art

 Since nonwoven fabrics have breathability and flexibility, they have been used in various applications in recent years, and their use is expanding. In addition, various characteristics according to the application are required, and further improvement in characteristics is required.

 In the field of sanitary materials such as disposable diapers and sanitary napkins, heat treatment and shrinkage of the non-woven fabric before and after its manufacture gives the sanitary material a fit and a tactile feel in addition to the above properties. . In recent years, there has been a demand for a sanitary material having further improved properties, and there has been a demand for the development of a nonwoven fabric which is appropriately shrunk, has excellent flexibility and good touch.

Japanese Patent Application Laid-Open No. 7-232409 discloses that a non-woven fabric using a composite fiber composed of two types of polyester resins having different heat shrinkage properties is heat-treated and heat-shrinked. However, Japanese Patent Application Laid-Open No. 7-232409 does not disclose specific heat shrinkage characteristics such as heat shrinkage. Also, this polyester resin The nonwoven fabric using was insufficient in bulk.

 JP-A-2002-146663 and JP-A-2002-146631 disclose nonwoven fabrics using a composite fiber comprising a propylene-based block copolymer and a polymer other than the propylene-based block copolymer. I have. However, JP-A-2002-146663 and JP-A-2002-146631 do not describe the heat shrinkage of nonwoven fabrics, and these nonwoven fabrics are not heat shrinkable. There was a problem with the lack of flexibility and tactile sensation. Purpose of the invention

 An object of the present invention is to provide a nonwoven fabric which is appropriately shrunk, has excellent flexibility and tactile sensation, a laminate using the nonwoven fabric, and a method for producing the same. Disclosure of the invention

 The inventor of the present invention heat-treats a spunbonded nonwoven fabric made of a specific conjugate fiber so that the spunbonded nonwoven fabric thermally shrinks to an extent that appropriate flexibility is obtained, and the resulting spunbonded nonwoven fabric is excellent. The present inventors have found that the present invention has excellent flexibility and tactile sensation, and completed the present invention.

 That is, the spunbonded nonwoven fabric according to the present invention,

At least two kinds of polymers selected from ethylene-based polymer (1), propylene-based block copolymer (2), and propylene-based polymer (3) other than propylene-based block copolymer (2) A spunbonded nonwoven fabric comprising the combined conjugate fiber (I), The spunbond nonwoven fabric has a specific volume of 10 cm ³ Zg or more, and the ethylene polymer (1) has a specific volume of 190. C, 2. 16 kg melt flow rate under a load (MFR) is 10~: l OO gZl O content, density 860~975 kg / m ^3, and the weight average molecular weight (Mw) to number average molecular weight (Mn) of (M w / Mn) force Si. 5 to 5,

 The propylene-based block copolymer (2) is composed of a portion insoluble in n-decane at 25 ° C (2-1) 20 to 70% by weight and a portion soluble in n-decane at 25 ° C (2-2) ) 80-30% by weight

 The insoluble part (2-1) is composed of a propylene polymer having an MFR (230 ° C, under a load of 2.16 kg) of 20 to 200 gZl 0 min, and has an ethylene unit and an α-carbon having 4 to 8 carbon atoms. The total content of olefin units is 10 mol% or less,

The soluble portion (2-2) is a copolymer of propylene with ethylene and Ζ or α-olefin having 4 to 8 carbon atoms, and is a total of ethylene units and α-olefin units having 4 to 8 carbon atoms. Content 20-70 mol ⁰ /. And the intrinsic viscosity []] is 2.0 d 1 / g or less.

It is characterized by:

 The propylene-based polymer (3) is preferably a propylene homopolymer or a random copolymer of propylene with ethylene and Z or haeofin having 4 to 8 carbon atoms.

The spunbonded nonwoven fabric according to the present invention has a heat shrinkage of 10% or more at 100 ° C and 30% or more at 120 ° C, and the ratio of the heat shrinkage between 120 ° C and 100 ° C (120.C / Preferably, the spunbond nonwoven fabric (a) having a temperature of 100 ° C) of 3 or less is obtained by heat treatment. The method for producing a spunbonded nonwoven fabric according to the present invention,

 At least two types of polymers selected from ethylene-based polymer (1), propylene-based block copolymer (2), and propylene-based polymer (3) other than propylene-based block copolymer (2) A method for producing a heat-shrinkable spunbonded nonwoven fabric, comprising heat-treating a spunbonded nonwoven fabric (a) composed of a composite fiber (i) obtained by combining the combined fibers.

 The spunbonded nonwoven fabric (a) has a heat shrinkage of 10% or more at 100 ° C and 30% or more at 120 ° C, and a ratio of heat shrinkage between 120 ° C and 100 ° C (1 20 ° C / 100 ° C) is 3 or less spunbond nonwoven fabric,

The ethylene polymer (1) has a melt flow rate (MFR) at 190 ° C. under a load of 2.16 kg of 10 to 100 minutes, a density of 860 to 975 kg gZm ³ , and a weight average molecular weight (Mw ) And the number average molecular weight (Mn) (Mw / Mn) force S1.5.

The propylene Proc copolymer (2) is, 25 ° C with n- decane-insoluble portion (2 1) 20 to 70 weight _^0/0 25 ° C with n- decane soluble part (2 — 2) 80-30% by weight,

The insoluble part (2-1) is composed of a propylene polymer having an MFR (230 ° C, under a load of 2.16 kg) of 20 to 200 gZl 0 min, and has ethylene units and 4 to 8 carbon atoms. the total content of Orefin unit is 10 mol _^0/0 or less,

The soluble portion (2-2) is a copolymer of propylene and ethylene and / or a C4-8 carbon olefin, and contains a total of ethylene units and an α-olefin unit having 4-8 carbon atoms. rate is 20 to 70 mole _^0/0, and an intrinsic viscosity [77] of 2. is O d lZg below. The laminate according to the present invention is characterized by having at least a layer made of any of the spunbonded nonwoven fabrics described above. Further, it is preferable to have at least a layer composed of the spunbonded nonwoven fabric (A) and a layer composed of the nonwoven fabric (B) having a specific volume smaller than that of the spunbonded nonwoven fabric (A).

 The spunbond nonwoven fabric (A) has a heat shrinkage of 10% or more at 100 ° C and 30% or more at 120 ° C, and a heat shrinkage ratio of 120 ° C and 100 ° C. The spunbonded nonwoven fabric (a) having (120 ° C / 100 ° C) of 3 or less is preferably a spunbonded nonwoven fabric obtained by heat treatment.

 The nonwoven fabric (B) is preferably a nonwoven fabric obtained by heat-treating a nonwoven fabric (b) having a heat shrinkage smaller than that of the spunbonded nonwoven (a).

 The method for producing a laminate according to the present invention,

 At least two types of polymers selected from ethylene-based polymer (1), propylene-based block copolymer (2), and propylene-based polymer (3) other than propylene-based block copolymer (2) A spunbond nonwoven fabric (a) composed of a composite fiber (i) obtained by combining

 A non-woven fabric (b) having a heat shrinkage smaller than that of the spunbond non-woven fabric (a);

A method for producing a laminate, comprising performing heat treatment after entanglement or heat fusion,

 The spunbond nonwoven fabric (a) has a heat shrinkage of not less than 10% at 100 ° C and not less than 30% at 120 ° C, and the ratio of the heat shrinkage between 120 ° C and 100 (120 (° C / 100 ° C) is 3 or less spunbond nonwoven fabric,

The ethylene polymer (1) melts at 190 ° C under 2.16 kg load. Flow rate (MFR) of 10-100 g / 10 min, density of 860-975 kg / m ³ , and ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (M w / Mn) force Si. 5 to 5,

 The propylene-based block copolymer (2) is composed of a portion insoluble in n-decane at 25 ° C (2-1) 20 to 70% by weight and a portion soluble in n-decane at 25 ° C (2-2) ) 80 to 30% by weight

The insoluble part (2_ 1), MFR (230 ° C, 2. under 16 kg load) becomes from propylene polymer is 20 to 200 _§ Bruno 10 minutes, and ethylene units and 4 to 8 carbon atoms α- The total content of olefin units is 10 mol. / ₀ or less,

The soluble portion (2-2) is a copolymer of propylene with ethylene and Ζ or α-olefin having 4 to 8 carbon atoms, and is a total of ethylene units and α-olefin units having 4 to 8 carbon atoms. a content of 20 to 70 mole _^0/0, and the intrinsic viscosity [eta] is 2. or less 0 d 1 / g. BRIEF DESCRIPTION OF THE FIGURES

 Figure 1 is a cross section of a composite fiber. (a) is a cross-sectional view of a side-by-side composite fiber, (b) is a cross-sectional view of a concentric core-sheath composite fiber, (c) is a cross-sectional view of an eccentric core-sheath composite fiber, and (d) is a parallel view. FIG. 1 is an example of a cross-sectional view of a core-sheath composite fiber. In the figure, 1 indicates a first polymer, 2 indicates a second polymer, 3 indicates a core, and 4 indicates a sheath. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the spunbonded nonwoven fabric according to the present invention and a laminate using the same will be described in detail. <Spunbond nonwoven fabric>

 The spunbond nonwoven fabric according to the present invention is selected from the group consisting of an ethylene polymer (1), a propylene block copolymer (2), and a propylene polymer (3) other than the propylene block copolymer (2). A heat-shrinkable spunbonded nonwoven fabric comprising a composite fiber (I) obtained by combining at least two types of polymers. Such a heat-shrinkable spunbonded nonwoven fabric is made of a propylene-based polymer (3) other than the ethylene-based polymer (1), the propylene-based block copolymer (2), and the propylene-based block copolymer (2). ^ It can be produced by heat-treating a spunbond nonwoven fabric (a) composed of a composite fiber (i) in which at least two selected polymers are combined.

 First, each component used in the present invention will be described.

 (1) Ethylene polymer:

 Examples of the ethylene polymer (1) used in the present invention include a homopolymer of ethylene and a copolymer of ethylene and α-olefin. Examples of the α-olefin include those having 3 to 8 carbon atoms, such as propylene, 1-butene, 1-hexene, 1-otaten, and 4-methyl-11-pentene. More specific examples of the ethylene polymer (1) include ethylene polymers such as low-density polyethylene, linear low-density polyethylene (ethylene-α-olefin copolymer), medium-density polyethylene, and high-density polyethylene. Can be In the present invention, these ethylene polymers may be used alone or as a mixture of two or more.

Such an ethylene-based polymer can be produced by a known method using a multi-site catalyst such as a Ziegler catalyst. Further, it can be produced by a known method using a single-site catalyst such as a meta-mouth catalyst. Of the ethylene polymers exemplified above, linear low-density polyethylene resin (ethylene- _α -olefin copolymer), medium-density polyethylene resin, and high-density polyethylene resin are particularly preferable from the comprehensive viewpoint of moldability into a nonwoven fabric. preferable. The ethylene-based polymer (1) has a menoleto flow rate (MFR) under a load of 190 ° C. and a load of 2.16 kg of 10 to: LOO gZl O content, preferably 12 to 90 g. The Z10 content is more preferably 14 to 85 g / 10 minutes. Here, the MFR of the ethylene polymer (1) is a value measured at a temperature of 190 ° C and a load of 2.16 kg by the method specified in ASTM D-1238. The MFR of the ethylene-based polymer (1) means the MFR of a simple substance when the ethylene-based polymer is used alone, and the MFR of the mixture when the ethylene-based polymer is mixed. Therefore, even if the MFR alone does not satisfy the above range, but the MFR satisfies the above range by mixing two or more kinds of ethylene polymers, this mixed The ethylene polymer can be used in the present invention as the ethylene polymer (1).

 The MFR of the ethylene polymer (1) affects the moldability and strength of the nonwoven fabric. That is, when the MFR of the ethylene polymer (1) is within the above range, the spunbonded nonwoven fabric has good moldability, and the heat-shrinked spunbonded nonwoven fabric also exhibits high strength. On the other hand, when the MFR of the ethylene polymer (1) is less than 10 g / 10 minutes, the formability of the spunbonded nonwoven fabric deteriorates, and the yarn is liable to be broken during spinning. If the MFR exceeds 100 g / 10 minutes, the fiber strength decreases, and the strength of the obtained spunbonded nonwoven fabric also decreases.

The density of the ethylene polymer (1) is 860 to 975 kgZm ³ , preferably 865 to 973 kg / m ³ , more preferably 905 to 975 kg / m ³ , particularly preferably 9 is a ^{1 0~ 9 7 3 k gZm 3} . The density of ethylene polymer (1) is It affects the physical properties and feel of the resulting spunbonded nonwoven fabric. If the density is less than 860 kg Zm ³ , the resulting spunbonded nonwoven fabric may have a poor touch. Also, if the density exceeds 9 7 5 k gZm ^3, too enhanced rigidity, tactile deteriorates.

 The ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the ethylene polymer (1) is 1.5 to 5. In the present specification, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are determined by gel permeation chromatography (GPC) using columns: T SKge 1 GMH6HTX 2, TS Kge 1 GMH6 -HTLX 2, Column temperature: 140. C, mobile phase: o-dichlorobenzene (ODCB), flow rate: 1. OmL no min, sample concentration: 3 OmgZ 20 mL-ODCB, injection volume: 500 L, measured in terms of polystyrene. For analysis, use 30 mg of a sample previously dissolved in 20 mL of o-dichlorobenzene with heating at 145 for 2 hours, and then filtering through a sintered filter with a pore size of 0.45 μm.

 Such an ethylene polymer (1) is contained in the conjugate fiber (i) in an amount in the range of 20 to 80% by weight.

 (2) Propylene block copolymer:

 The propylene-based block copolymer used in the present invention has a portion insoluble in n-decane at 25 ° C (2-1) 20 to 70% by weight and a portion soluble in n-decane at 25 (2 -2) 80 to 30% by weight.

The insoluble portion (2-1) is made of a propylene polymer having an MFR (230 ° C, under a load of 2.16 kg) of 20 to 200 gZl 0 minutes, and has ethylene units and carbon atoms of 4 to 8 Roh total content of α- Orefin units is 1 0 mole _^0/0 or less. Here, the MFR of the propylene polymer is determined by the method specified in ASTM D-1238. It is a value measured under the conditions of a temperature of 230 ° C and a load of 2.16 kg. The soluble portion (2-2) is a copolymer of propylene and ethylene and Z or a C4 to C8 olefin, and contains a total of ethylene units and C4 to C8 _α -olefin units. Ratio is 20 to 70 mol%, and the intrinsic viscosity [η] force is S 2. OdlZg or less.

 Here, “ethylene unit” means a structural unit derived from ethylene, and “a monoolefin unit having 4 to 8 carbon atoms” means a structural unit derived from α-olefin having 4 to 8 carbon atoms. I do.

 Examples of the α-olefin having 4 to 8 carbon atoms used in the propylene-based block copolymer (2) include a linear or branched α-olefin. Specific examples include 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-11-pentene. Of these, 1-peptene is particularly preferred. Such a propylene block copolymer (2) can be produced by a known method. For example, a component capable of forming the insoluble portion (2-1) and the soluble portion (2-2) are It can be produced by mechanically mixing a component which can be formed in a molten state. Further, a component capable of forming the insoluble portion (2-1) and a component capable of forming the soluble portion (2-2) using an olefin polymerization catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst. Can be produced by sequential polymerization in two steps by a known method.

 In such a propylene block copolymer (2), a portion (2-1) insoluble in η-decane and a portion (2-2) soluble in η-decane at 25 ° C are well dispersed. As a result, the spinnability at the time of producing the spunbonded nonwoven fabric is excellent, and the heat-shrinkable spunbonded nonwoven fabric also has excellent flexibility.

Such a propylene block copolymer (2) is used as the composite fiber (i). 20-80 weight. Included in quantities in the range / ₀ .

 (3) Propylene polymer:

 The propylene-based polymer (3) used in the present invention is a propylene-based polymer other than the propylene-based block copolymer (2). Examples of such a propylene-based polymer (3) include a propylene homopolymer and a random copolymer of propylene with ethylene and / or a olefin having 4 to 8 carbon atoms (hereinafter referred to as “propylene-based random copolymer”). Coalescence).

Examples of the propylene homopolymer include crystalline homopolypropylene having an isotactic index of preferably 90 or more. The propylene Ren system in the random copolymer, the total content of ethylene units and the number of 4-8 carbon α- O Les fin unit is preferably 10 mol% or less, more preferably 0.05 to 10 moles ⁰ /. It is.

 Examples of the α-olefin having 4 to 8 carbon atoms used in the propylene-based polymer (3) include a linear or branched α-olefin. Specifically, 1-butene, 1-pentene, 1-hexene, 1-year-old octene, 4-methinolay 1-pentene are mentioned. Of these, 1-butene is particularly preferred.

 The MFR (at 230 ° C. under a load of 2.16 kg) of the propylene-based polymer (3) is preferably 10 to 200 gZlO, more preferably 20 to 150 g / l0 min. Here, the MFR of the propylene-based polymer (3) is a value measured under the conditions of a temperature of 230 ° C and a load of 2.16 kg by a method specified in ASTM D-1238.

The ratio (MwZMn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the propylene-based polymer (3) is preferably 1.5 to 5, and has excellent spinnability and particularly excellent fiber strength. From the viewpoint of obtaining a composite fiber, 1.5 to 3.0 is more preferable. Such a propylene-based polymer (3) is contained in the conjugate fiber (i) in an amount ranging from 20 to 80% by weight.

 (Additive)

 In the present invention, in addition to the above polymers (1) to (3), various additives may be used as needed within a range not to impair the object of the present invention. Specific additives include heat stabilizers, various stabilizers such as weathering stabilizers, fillers, antistatic agents, hydrophilic agents, slip agents, antiblocking agents, antifogging agents, lubricants, dyes, pigments, and natural Oil, synthetic oil, wax and the like. Conventionally known additives can be used as these additives.

 Examples of stabilizers include anti-aging agents such as 2,6-di-t-butyl-14-methylphenol (BHT); tetrakis [methylene-13- (3,5-di-t-butynole 4-hydroxyphenyl)] Propionate] methane, β- (3,5-di-t-butyl-14-hydroxyphenyl) propionic acid alkyl ester, 2, 2'-oxamidobis [ethyl-3_ (3,5-di-t-butyl-14) Phenolic antioxidants such as propionate, Irganox 1010 (trade name, hindered phenolic antioxidant); zinc stearate, calcium stearate, 1,2-hydroxyxesteric acid Metal salts of fatty acids such as calcium; glycerin monostearate, glycerin distearate, pentaerythri tonolemonostearate, pentaerythris Tonorejisute Areto, polyhydric alcohol fatty acid esters such as Pentaerisuri tall tristearate and the like. These stabilizers may be used alone or in combination of two or more.

Examples of fillers include silica, kieselguhr, alumina, titanium oxide, magnesium oxide, pumice powder, pumice balloon, aluminum hydroxide, and magnesium hydroxide. Shim, Basic magnesium carbonate, Dolomite, Calcium sulfate, Potassium titanate, Barium sulfate, Calcium sulfite, Tanolek, Clay, My strength, Asbestos, Calcium silicate, Montmorillonite, Bentonite, Graphite , Aluminum powder, molybdenum sulfide and the like.

 (a) Spunbond nonwoven fabric:

 The spunbond nonwoven fabric (a) used in the present invention comprises at least two types of polymer selected from the above-mentioned ethylene polymer (1), propylene block copolymer (2) and propylene polymer (3). It is a spunbonded nonwoven fabric made of a composite fiber (i) obtained by combining the union. Here, the term “composite fiber” means that the ratio between the length and the diameter when the cross section is assumed to be a circle is called fiber! / Means a single fiber having two or more phases. Therefore, the conjugate fiber (i) is a single fiber containing at least two types of fibrous phases formed by a polymer selected from the polymers (1) to (3). Examples of such composite fibers (i) include core-sheath type composite fibers and side-by-side type composite fibers. More specifically, as a core-sheath composite fiber, a coaxial composite fiber in which the center of a circular core and the center of a donut-shaped sheath part match in a fiber cross section; the center of the core part and the sheath part Eccentric conjugate fiber with different core and core covered with sheath; parallel with core not completely covered with sheath, with different core center and sheath center Type composite fibers. Among these, the side-by-side type, the eccentric type and the side-by-side type composite fiber are preferable, and the side-by-side type and the side-by-side type composite fiber are particularly preferable. Fig. 1 shows the cross sections of various composite fibers. In FIG. 1, (a) is a cross-sectional view of a side-by-side composite fiber, (b) is a cross-sectional view of a concentric composite fiber, (c) is a cross-sectional view of an eccentric composite fiber, and (d) is a cross-sectional view of a parallel composite fiber. It is an example of a sectional view.

Thus, at least two kinds of polymers among the above polymers (1) to (3) By forming the composite fiber (i) by combining, the spunbond nonwoven fabric (a) composed of the composite fiber (i) has an appropriate heat shrinkability. In the present invention, the heat shrinkage of the spunbond nonwoven fabric (a) is 100. It is 10% or more at C and 30% or more at 120 ° C, and the ratio of heat shrinkage between 120 ° C and 100 (120 ° C / 100 ° C) is 3 or less, preferably Is preferably 2.5 or less, more preferably 2 or less. The heat shrinkage at 140 ° C. is preferably 95% or less. When the heat shrinkage of the spunbonded nonwoven fabric (a) is within the above range, the heat-shrinkable spunbonded nonwoven fabric obtained by heat-treating the spunbonded nonwoven fabric (a) has excellent flexibility. When the ratio of the heat shrinkage between 120 ° C. and 100 ° C. is in the above range, the temperature change of the heat shrinkage is small, and the temperature control during the heat treatment becomes easy. In the present invention, the heat shrinkage is a value measured by the method described in JISL 1906. The heat shrinkage of the composite fiber (i) is 100% or more at 100 and 30% or more at 120 ° C, and the ratio of the heat shrinkage between 120 ° C and 100 ° C (1 20 ° C / 100 ° C) is 3 or less, preferably 2.5 or less, and more preferably 2 or less. The heat shrinkage at 140 ° C. is preferably 95% or less. When the heat shrinkage of the conjugate fiber (i) is in the above range, a spunbonded nonwoven fabric having a heat shrinkage in the above range can be easily obtained. When the ratio of the heat shrinkage between 120 ° C. and 100 ° C. is within the above range, the temperature change of the heat shrinkage is small, and the temperature control during the heat treatment becomes easy. The fineness of the spunbond nonwoven fabric (a) is preferably 8.0 denier or less, and more preferably 5.0 denier or less because a nonwoven fabric having more excellent flexibility can be obtained.

The basis weight (mass per unit area) of the spunbond nonwoven fabric (a) is preferably from 10 to 100 g / m ² , and more preferably from 12 to 90 gZm ² .

(Preparation method of spunbond nonwoven fabric (a)) The spunbonded nonwoven fabric (a) can be prepared by a conventionally known spunbonding method as long as it can form the core-sheath type composite fiber or the side-by-side type composite fiber as described above.

 Hereinafter, a method for preparing a spunbonded nonwoven fabric (a) composed of side-by-side type composite fibers using two types of polymers among the above polymers (1) to (3) will be specifically described. First, two types of polymers among the above-mentioned polymers (1) to (3) are individually melted using an extruder or the like. At this time, if necessary, the above additive may be mixed with one or both of the two polymers. These two types of polymers are discharged from a spinneret having a composite spinning nozzle configured to form a desired side-by-side structure, and a side-by-side type composite filament is spun out. The spun conjugate fiber is cooled by a cooling fluid, and tension is applied to the conjugate fiber by drawing air to adjust the fineness to a predetermined fineness, which is collected on a collection belt to a predetermined thickness. Deposit. Next, a confounding treatment using a needle punch, a water jet, an ultrasonic seal, or the like, and a heat fusion using a hot embossing roll are performed to obtain a spunbond nonwoven fabric (a) made of a composite fiber having a desired side-by-side structure. In the case of heat fusion using a hot embossing roll, the embossing area ratio of the embossing roll can be determined as appropriate, but is usually preferably 5 to 30%.

 The spunbond nonwoven fabric (a) composed of the core-sheath type composite fiber is prepared by changing the spinneret to a spinneret having a composite spinning nozzle configured to form a desired core-sheath structure. Can be.

 (Heat treatment of spunbond nonwoven fabric (a))

The spunbonded nonwoven fabric according to the present invention can be obtained by subjecting the spunbonded nonwoven fabric (a) prepared by the above method to heat shrinkage by performing a heat treatment using a heating device such as an oven. Heating equipment can be either continuous or batch heating May be used. Instead of a heating device such as an oven, hot air may be directly applied to the spunbond nonwoven fabric (a).

 The heat treatment temperature is usually 90 ° C or higher, preferably 95 ° C or higher, more preferably 100 ° C or higher, and usually 140 ° C or lower, preferably 135 ° C or lower, more preferably 130 ° C or lower. It is as follows. The heating time is usually at least 20 seconds, preferably at least 30 seconds, more preferably at least 40 seconds, and usually at most 180 seconds, preferably at most 150, more preferably at most 120 seconds.

 The heat-shrinkable spunbond nonwoven fabric thus obtained is

(1) 190. C, 2. 16 kg agate Leto flow rate under load (MFR) is 1 0~: LOO gZl 0 min, a density of 860~975 k gZm ^3, and a weight average molecular weight (Mw) to number average molecular weight ( An ethylene polymer having a ratio (Mw / Mn) of 1.5 to 5 with respect to Mn);

(2) 25 ° C in n- decane-insoluble portion (2 1) 20 to 70 wt% and the portion soluble in n- decane at 25 ° C (2-2) 80 to 30 weight _^0/0 A propylene-based block copolymer comprising:

The insoluble part (2-1) is composed of a propylene polymer having an MFR (230 ° C, under a load of 2.16 kg) of 20 to 200 gZl 0 minutes, and has ethylene units and C4 to C8 olefin units. and a total content of 10 mole _^0/0 or less,

 The soluble part (2-2) is composed of propylene and ethylene and Z or carbon number.

A copolymer of Fei one Orefuin of. 4 to 8, Q of ethylene units and 4 to 8 carbon atoms; - the total content of 20 to 70 moles of Orefuin Units _^0/0, and the intrinsic viscosity [eta Is less than 2. Od lZg

A propylene-based block copolymer; and (3) A spunbond nonwoven fabric comprising a composite fiber (I) in which at least two kinds of polymers selected from propylene-based polymers other than the propylene-based block copolymer (2) are combined. The conjugate fiber (I) is a fiber obtained by heat-shrinking the conjugate fiber (i). This heat-shrinkable spunbonded nonwoven fabric has a specific volume of 10 cm ³ / g or more, preferably 11 cm ³ / g or more, and is excellent in flexibility and touch. The upper limit of the specific volume is not particularly limited, but is preferably 30 cm ³ Zg or less, and more preferably 20 cm ³ Zg or less.

This heat shrunk spunbonded nonwoven fabric, the basis weight is preferably 10~200 gZm ^2. The bending resistance according to the 45 ° cantilever method is preferably 4 Omm or less, more preferably 30 mm or less, particularly preferably 20 mm or less in the flow direction, and preferably 4 Omm or less, more preferably 3 Omm in the transverse direction. Or less, particularly preferably 2 Omm or less. The weight per unit area and the bending resistance according to the 45 ° cantilever method are values measured by the method described in JISL 1096.

 The spunbonded nonwoven fabric according to the present invention is a nonwoven fabric that is excellent in shrinkage and flexibility, excellent in extensibility, heat sealability, strength, and spinnability, and excellent in fuzz resistance. Such spunbonded nonwoven fabric is suitably used for various uses such as medical products, sanitary materials, and packaging materials. Particularly, it is preferably used as a member for sanitary materials such as disposable diapers and sanitary napkins.

 Ku laminated body>

 Hereinafter, the laminate according to the present invention will be described.

The laminate according to the present invention is a laminate having at least a layer made of the heat-shrinkable spunbonded nonwoven fabric (hereinafter referred to as “spunbonded nonwoven fabric (A)”). Such a laminate includes a layer made of spunbond nonwoven fabric (A) and A laminate having at least a layer made of the nonwoven fabric (B) having a specific volume smaller than that of the bonded nonwoven fabric (A) is preferable. The nonwoven fabric (B) is not particularly limited as long as the specific volume satisfies the above relationship, and may be the spunbond nonwoven fabric according to the present invention.

 The laminate having two layers of the spunbond nonwoven fabric (A) and the nonwoven fabric (B) whose specific volume satisfies the above relationship has excellent bulkiness.

 Further, the nonwoven fabric (B) is preferably a nonwoven fabric obtained by heat-treating a nonwoven fabric (b) having a heat shrinkage smaller than that of the spunbond nonwoven (a). Examples of such non-woven fabric (b) include polyolefin fibers such as polypropylene and polyethylene; polyester fibers such as polyethylene terephthalate and polybutylene terephthalate; polyamide fibers such as nylon 6 and nylon 66; recycled fibers such as rayon; Non-woven fabrics made of natural fibers such as cotton and polyester.

 Further, the nonwoven fabric (b) may be a spunbonded nonwoven fabric before the heat treatment used in the present invention as long as the heat shrinkage satisfies the above relationship.

 By using a spunbonded nonwoven fabric (a) and a nonwoven fabric (b) whose heat shrinkage satisfies the above relationship, a laminate having excellent bulkiness can be obtained.

The laminate according to the present invention is obtained by laminating the above spunbonded nonwoven fabric (a) and the above nonwoven fabric (b), then performing entanglement treatment using a needle punch, a water jet, an ultrasonic seal, etc. It is manufactured by subjecting them to heat treatment. It can also be produced by laminating a spunbonded nonwoven fabric (A) obtained by heat-treating a spunbonded nonwoven fabric (a) and a nonwoven fabric (B) obtained by heating a nonwoven fabric (b). Of these, the former method is preferably used. This heat treatment can be performed under the same conditions as the heat treatment conditions for the spunbonded nonwoven fabric (a) described above. Example

 Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples. First, methods for measuring physical properties used in Examples and Comparative Examples will be described.

 (1) Measurement of heat shrinkage:

 The heat shrinkage of the non-woven fabric is measured by taking three specimens of about 25 cm x 25 cm from the non-woven fabric before the heat treatment per 3 m of sample width, and leaving them at the measurement temperature of 100 ° C or 120 ° C. Was set to 60 seconds and measured according to the method described in JISL 1906.

 (2) Measurement of basis weight:

 The basis weight of the nonwoven fabric was measured according to the method described in JIS L1906.

 (3) Measurement of tensile strength and elongation:

 Five test pieces with a flow direction (MD) force of 50 mm and a lateral direction (CD) of 25 mm and five test pieces with a flow direction (MD) of 25 mm and a lateral direction (CD) of 15 Omm were collected from the nonwoven fabric. The former test piece was subjected to a tensile test using a constant-speed elongation type tensile tester under the conditions of 10 mm between chucks and 100 mmZ for a tensile speed. The maximum load in the flow direction, the rate of extension of the test piece at the time of maximum load and at the time of breakage were measured, and the average value of five test pieces was determined. Similarly, the latter test piece was subjected to a tensile test, and the maximum load in the lateral direction, the rate of extension of the test piece at the maximum load and at the time of breakage were measured, and the average value of five test pieces was obtained.

(4) Measurement of bending resistance by 45 ° cantilever method: From the nonwoven fabric, three test pieces with a flow direction (MD) force of 50 mm and a lateral direction (CD) of 20 mm and three test pieces with a flow direction (MD) of 20 mm and a lateral direction (CD) of 15 Omm were collected. did. Using the former test piece, the rigidity in the flow direction was measured in accordance with the method described in JISL 1096, and the average value of three test pieces was determined. Using the latter test piece, the transverse softness was measured in accordance with the method described in JISL 1096, and the average value of the three test pieces was determined.

 (5) Measurement of the softness by the handle ometer method:

 Three test pieces with a flow direction (MD) of 100 mm and a transverse direction (CD) of 100 mm were collected from the nonwoven fabric. With respect to this test piece, the bending stiffness in the flow direction (MD) and the transverse direction (CD) were measured in accordance with the method described in JIS L1096. The average value of the three test pieces was defined as the softness of the nonwoven fabric.

 (6) Specific volume:

 The thickness of the nonwoven fabric after the heat treatment was measured according to JIS L1906. Next, using the basis weight measured in the above (2), the specific volume of the nonwoven fabric was determined by the following equation.

 Specific volume (unit: cmVg) = thickness Z weight

 (7) Tactile sensation:

 The touch feeling of the obtained laminate was evaluated according to the following criteria.

 A: remarkably good

 B: Good

 C: Same as non-woven fabric

 (8) Bulkiness:

 The bulkiness of the obtained laminate was evaluated according to the following criteria.

 A: remarkably good

B: Good C: Same as non-woven fabric

 <Example 1>

Insoluble part of polypropylene as a component for forming the (2_ 1) (mp = 140 ° C, MFR (230 ° C, 2. 16 kg load) ^ e O gZl O content, the ethylene unit content = 4. 0 mol. / ₀ ) 40% by weight of propylene ethylene glycol (intrinsic viscosity [77] = 1.59 dLZg, ethylene unit content = 30 mol ⁰ / ₀₎ 60 weight _{^0/0 using} propylene block copolymer polymers consisting of (BPP) used as a sheath, mp 162 ° C, MFR (230 ° C, 2. 16 kg load) 60 GZL 0 minutes and MwZMn 2. Using the homopolypropylene (HPP) of No. 5 as the core, composite melt spinning was performed, and parallel core-sheath type composite fibers having a core / sheath weight ratio of 20Z80 were deposited on the collecting surface. Next, this deposit was heated and pressurized with an embossing roll (emboss area ratio: 18%) to prepare a spunbond nonwoven fabric (a-1) having a basis weight of 20 g and a fineness of constituent fibers of 3 denier. Each physical property of the obtained spun pound nonwoven fabric (a-1) before the heat treatment was measured. Table 1 shows the results.

 The spunbond nonwoven fabric (a-1) was introduced into an oven and heated at 120 ° C. for 60 seconds to obtain a heat-shrinkable spunbond nonwoven fabric (A-1). The properties of this spunbond nonwoven fabric (A-1) were measured. Table 1 shows the results.

In addition, melt spinning is performed using only the homopolypropylene (HPP), fibers of the mono component are deposited on the collecting surface, and the deposit is heated and pressurized (emboss area ratio: 18%) with an embossing roll. A spunbond nonwoven fabric (b-1) having a basis weight of 20 g / m ² and a fineness of constituent fibers of 3 denier was produced. The heat shrinkage of this spanbond nonwoven fabric (b-1) at 120 ° C was 0%. The spunbond nonwoven fabric (b-1) was obtained by heating at 120 ° C for 60 seconds. The specific volume of the heat-shrinked spunbond nonwoven fabric (B-1) was 8.6 cm ³ Zg.

 After laminating the spunbonded nonwoven fabric (a-1) and the spunbonded nonwoven fabric (b-1), they are heat-sealed with a hot embossing roll (emboss area ratio: 10%) to produce a laminated body (1). did. The heat shrinkage of this laminate (1) at 120 ° C. was measured. Further, the laminate (1) was introduced into an oven, and heated at 120 ° C. for 60 seconds to obtain a heat-shrinkable laminate. The tactile feel and bulkiness of this laminate were evaluated.

Table 1 shows the results.

 <Example 2>

Instead of propylene block copolymer (BPP), ethylene homopolymer (PE 1) (density = 0.948 g / cm ³ , MFR (190 ° C, 2.16 kg load) = 30 _§ A spunbonded nonwoven fabric (a-2) was produced in the same manner as in Example 1 except that (Mw / Mn = 3.0) was used for 10 minutes. Each physical property of the obtained spunbond nonwoven fabric (a-2) was measured.

 The spunbonded nonwoven fabric (a-2) was heat-treated in the same manner as in Example 1 to obtain a heat-shrinkable spunbonded nonwoven fabric (A-2). The properties of the spunbond nonwoven fabric (A-2) were measured. Table 1 shows the results.

 Further, a laminate (2) was produced in the same manner as in Example 1, and the heat shrinkage at 120 ° C. was measured. Further, the laminate (2) was heat-treated to produce a heat-shrinkable laminate in the same manner as in Example 1, and the feel and bulkiness of the laminate were evaluated. Table 1 shows the results.

 Example 3>

Instead of propylene block copolymer (BP P), ethylene copolymer (PE 2) (density = 0.930 g / cm ³ , MFR (190 ° C, 2.16 kg load) (Weight) = 60 gZlO content, MwZMn = 2.7), except that spunbond nonwoven fabric (a-3) was prepared in the same manner as in Example 1. Each physical property of the obtained spunbonded nonwoven fabric (a-3) was measured.

 The spunbonded nonwoven fabric (a-3) was heat-treated in the same manner as in Example 1 to obtain a heat-shrinkable spunbonded nonwoven fabric (A-3). Each physical property of this spunbonded nonwoven fabric (A-3) was measured. Table 1 shows the results.

Further, a laminate (3) was produced in the same manner as in Example 1, and the heat shrinkage at 120 ° C. was measured. Further, the laminate (3) was subjected to heat treatment to produce a heat-shrinkable laminate in the same manner as in Example 1, and the feel and bulkiness of the laminate were evaluated. Table 1 shows the results.

table 1

MD: Flow direction, CD: Lateral direction <Comparative Example 1>

Melt spinning was performed using only the homopolypropylene (HPP) used in Example 1 to deposit monocomponent fibers on the collecting surface. Next, the sediment is heated and pressed with an embossing roll (emboss area ratio: 18%) to produce a spunbond nonwoven fabric (a-4) having a basis weight of 20 g / m ² and a fineness of constituent fibers of 3 denier. did. Each physical property of the obtained spunbond nonwoven fabric (a-4) before the heat treatment was measured. Table 2 shows the results.

 The spunbonded nonwoven fabric (a-4) was heat-treated in the same manner as in Example 1 to obtain a heat-shrinkable spunbonded nonwoven fabric (A-4). Each physical property of this spunbond nonwoven fabric (A-4) was measured. Table 2 shows the results.

 Further, a laminate (4) was produced in the same manner as in Example 1, and the heat shrinkage at 120 ° C. was measured. Further, the laminate (4) was heat-treated to produce a heat-shrinkable laminate in the same manner as in Example 1, and the feel and bulkiness of the laminate were evaluated. Table 2 shows the results.

 <Comparative Example 2>

Melting spinning was performed using only propylene / ethylene random copolymer (RPP) with a melting point of 138 ° C and MFR = 60 g / 10 minutes, and monocomponent fibers were deposited on the collection surface. Next, this deposit was heated and pressed with an embossing roll (emboss area ratio: 18%) to produce a spunbond nonwoven fabric (a-5) with a basis weight of 20 gm ² and a fineness of constituent fibers of 3 denier. . Each physical property of the obtained spun bond nonwoven fabric (a-5) before the heat treatment was measured. Table 2 shows the results.

The spunbonded nonwoven fabric (a-5) was heat-treated in the same manner as in Example 1 to obtain a heat-shrinkable spunbonded nonwoven fabric (A-5). The properties of the spunbond nonwoven fabric (A-5) were measured. Table 2 shows the results. Further, a laminate (5) was produced in the same manner as in Example 1, and the heat shrinkage at 120 ° C. was measured. Furthermore, the laminate (5) was subjected to heat treatment to produce a heat-shrinkable laminate in the same manner as in Example 1, and the feel and bulkiness of the laminate were evaluated. Table 2 shows the results.

 Comparative Example 3>

Melt spinning was performed using only the propylene-based block copolymer (BPP) used in Example 1, and monocomponent fibers were deposited on the collecting surface. Next, this deposit is heated and pressurized with an embossing roll (emboss area ratio 18%) to produce a spun-pound nonwoven fabric (a-16) with a basis weight of 20 g / m ² and a fineness of constituent fibers of 3 denier. did. Each physical property of the obtained spunbonded nonwoven fabric (a-6) before the heat treatment was measured. Table 2 shows the results.

 The spunbonded nonwoven fabric (a-6) was heat-treated in the same manner as in Example 1 to obtain a heat-shrinkable spunbonded nonwoven fabric (A-6). The properties of this spunbond nonwoven fabric (A-6) were measured. Table 2 shows the results.

Further, a laminate (6) was produced in the same manner as in Example 1, and the heat shrinkage at 120 ° C. was measured. Further, the laminate (6) was heat-treated to produce a heat-shrinkable laminate in the same manner as in Example 1, and the feel and bulkiness of the laminate were evaluated. Table 2 shows the results. Table 2

MD: Flow direction, CD: Lateral direction Industrial applicability

 According to the present invention, it is possible to obtain a spunbonded nonwoven fabric which is appropriately shrunk, has excellent strength, extensibility, and spinnability, has good flexibility and fuzz resistance, and has a good balance. It can be suitably used as a member for various industries such as products, sanitary materials, and packaging materials. In particular, it can be preferably used as a member for sanitary materials such as disposable diapers and sanitary napkins.

Claims

The scope of the claims 1.  At least two types of polymers selected from ethylene-based polymer (1), propylene-based block copolymer (2), and propylene-based polymer (3) other than propylene-based block copolymer (2) A spunbond nonwoven fabric composed of a composite fiber (I) obtained by combining The specific volume of the spunbond nonwoven fabric is 10

That's it, The ethylene polymer (1) is, 190 ° C, 2. 16 kg melt flow rate under a load (MFR) is 10~: l OO gZl O content, density 860~ 975 k gZm ^3, and the weight average The ratio (Mw / Mn) of the molecular weight (Mw) to the number average molecular weight (Mn) is 1.5 to 5,  The propylene block copolymer (2) is composed of a portion insoluble in n-decane at 25 ° C. (2-1) 20-70 wt% and a portion soluble in n-decane at 25 ° C. (2_2 ) 80 to 30% by weight, The insoluble part (2-1) is composed of a propylene polymer having an MFR (230 ° C, under a load of 2.16 kg) of 20 to 200 g / l 0 minutes, and has an ethylene unit and 4 to 8 carbon atoms. the total content of CK- Orefin units is 10 mol _^0/0 or less,  The soluble part (2-2) is composed of propylene and ethylene and Z or carbon number. A copolymer with 4 to 8 alpha-Orefuin, the total content of ethylene units and having a carbon number of 4 ~ 8 alpha-Orefuin units 20 to 70 mole ⁰ /. And the intrinsic viscosity [η] is 2.0 d 1 / g or less. A spunbond nonwoven fabric characterized by the above-mentioned. 2.  2. The spunbonded nonwoven fabric according to claim 1, wherein the propylene-based polymer (3) is a propylene homopolymer or a random copolymer of propylene with ethylene and / or haloolefin having 4 to 8 carbon atoms. . 3.  Span-bonded nonwoven fabric with a heat shrinkage of 10% or more at 100 and 30% or more at 120, and a heat shrinkage ratio of 120 ° C to 100 ° C (120 ° CZl 00 ° C) of 3 or less The spunbonded nonwoven fabric according to claim 1, which is obtained by subjecting (a) to a heat treatment. Four.  At least two kinds of polymers selected from ethylene-based polymer (1), propylene-based block copolymer (2), and propylene-based polymer (3) other than propylene-based block copolymer (2) A method for producing a heat-shrinkable spunbonded nonwoven fabric, characterized by heating the spunbonded nonwoven fabric (a) comprising the combined conjugate fiber (i),  (A) The force S, the heat shrinkage is 10% or more at 100 ° C and 30% or more at 120 ° C, and the ratio of the heat shrinkage between 120 ° C and 100 ° C (120 ° C) (CZ 100 ° C) is 3 or less spunbond nonwoven fabric, The ethylene polymer (1) is, 190 ° C, 2. 16 kg melt flow rate under a load (MFR) is 10~: LOO gZl O content, density 860~975 k gZm ^3, and weight-average molecular weight (Mw) and the number average molecular weight (Mn) w / Mn) force Si. 5 to 5,  25. The propylene-based block copolymer (2). In C, the portion insoluble in n-decane (2-1) is composed of 20-70% by weight, and in 25, the portion soluble in n-decane (2-2) is 80-30% by weight,  The insoluble part (2-1) has MFR (230 ° C, under 2.16 kg load) 20-200 consists g Bruno 10 minutes at a propylene polymer, and the total content of ethylene units and α- old olefin units having 4 to 8 carbon atoms is 10 mol _^0/0 or less,  The soluble portion (2-2) is a copolymer of propylene with ethylene and Ζ or α-olefin having 4 to 8 carbon atoms, wherein ethylene units and The total content of 8 of α- Orefin units are 20-70 Monore _^0/0, and the intrinsic viscosity [eta] is 2. 0 d 1 Z g or less A method for producing a spunbonded nonwoven fabric. Five.  A laminate having at least a layer made of the spun-pound nonwoven fabric according to any one of claims 1 to 3. 6. A laminate having at least a layer composed of the spunbonded nonwoven fabric (A) according to claim 1 and a nonwoven fabric (B) having a specific volume smaller than the specific volume of the spunbonded nonwoven fabric (A). body. 7.  The spunbond nonwoven (A) force  Heat shrinkage 10 at 100 ° C. /. Heat treatment is performed on a spanbond nonwoven fabric (a) with a heat shrinkage ratio of 120 ° C and 100 ° C (120 ° CZl00 ° C) of 3 or less, which is 30% or more at 120 and 100 ° C. 7. The laminate according to claim 6, wherein the laminate is a spunbond nonwoven fabric obtained by the above method. 8.  The non-woven fabric (B) is a non-woven fabric obtained by heat-treating a non-woven fabric (b) having a heat shrinkage smaller than that of the spunbonded non-woven fabric (a). 13. The laminate according to item. 9.  At least two kinds of polymers selected from ethylene-based polymer (1), propylene-based block copolymer (2), and propylene-based polymer (3) other than propylene-based block copolymer (2) A spunbond nonwoven fabric (a) composed of a combined conjugate fiber (i),  A non-woven fabric (b) having a heat shrinkage smaller than that of the spunbond non-woven fabric (a); A method for producing a laminate, comprising performing heat treatment after entanglement or heat fusion, (A) Force The heat shrinkage is 10% or more at 100 ° C and 30% or more at 120, and the ratio of the heat shrinkage between 120 ° C and 100 (120 ° C / ¥ 00 ° C) is 3 or less spunbond nonwoven fabric, The ethylene polymer (1) has a menoleto flow rate (MFR) at 190 ° C and a load of 2.16 kg of 10 to 100 g / 100 min, and a density of 860 to 975. k and the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / Mn) is 1.5 to 5,  The propylene block copolymer (2) has a portion insoluble in n-decane at 25 ° C. (2_1) 20-70% by weight and a portion soluble in n-decane at 25 ° C. (2-2) ) 80 to 30% by weight, The insoluble portion (2-1) is composed of a propylene polymer having an MFR (230 ° C, under a load of 2.16 kg) of 20 to 200 g / 10 minutes, and has ethylene units and carbon number. the total content of 4-8 single Orefin unit is 1 0 mole _^0/0 or less, The soluble portion (2-2) is a copolymer of propylene and ethylene and Z or α-olefin having 4 to 8 carbon atoms, and contains a total of ethylene units and 4-olefin carbon units. rate is 20 to 70 mole _^0/0, and an intrinsic viscosity [77] of 2. O dl Zg less A method for producing a laminate,